This invention relates to a film forming method for supplying a solution containing solid contents onto a to-be-processed substrate to form a liquid-like film and, through the volatilization of a solvent in the solution, forming a film of the solid contents on the substrate.
After coating a liquid-like resist film containing solid contents, such as a photosensitive material, in a solvent onto a to-be-processed substrate, such as a wafer, and, through the volatilization of the solvent, forming a solid-like resist film, the resist film for use in a patterning step is exposed with light and developed.
For the coating of a resist solution, the thus far adopted spin-coating method easily forms a uniform film on the surface of a to-be-processed substrate, but there is a problem in that a film is formed also on an alignment area, positional displacement measuring area and substrate's outer periphery, which are not required for an anti-reflection film and resist film, and, for this reason, alignment accuracy is lowered upon exposure with light.
By the use of solution supply nozzles equipped with an interrupt function it is possible to selectively form a solution film onto the substrate. In this method, it is possible to selectively coat the solution film on a wide area of about 100 .mu.m square, but it has not been possible to selectively do so on a narrow area of below a few tens of .mu.m square.
This problem is not restricted to the resist film and a common problem arises in the formation of a solution film by supplying a solution.